| 摘要 |
PROBLEM TO BE SOLVED: To realize stationary reduction of position measuring time in positioning equipment using a GPS. SOLUTION: This positioning equipment stores ephemeris and its obtained time when the ephemeris is obtained (steps SA6-SA8). After that, elapsed time after the ephemeris is obtained is calculated every one minute (steps SA10-SA12). After the process has passed two hours, an alarm sound is generated every two minutes (SA13-SA14). The alarm sound urges a user to perform measuring operation continuously for 30 seconds or longer at a place excellent in receiving environment of a radio wave before validity of the ephemeris is expired. It can be prevented that the position measuring time is increased by using ephemeris lacking in effectiveness, and provability that position measurement is possible in a short time is improved. During position measurement (YES in step SA9), the informing by the alarm sound is interrupted, and deterioration of measuring precision due to noise is prevented. |
